Clinicians should screen for syphilis in asymptomatic, nonpregnant patients who are at increased risk for the infection, according to a new draft recommendation statement by the U.S. Preventive Services Task Force (USPSTF).
Overall, the USPSTF found “convincing evidence” of substantial benefit in screening these patients. The Grade A draft recommendation statement, published Dec. 14, updates information on prevalence and risk factors, as well as data on newer screening tests, that have become available since the Task Force's 2004 recommendation on this topic.
In 2013, the U.S. had 17,375 reported cases (5.5 cases per 100,000 persons) of primary and secondary syphilis, according to the draft. Surveillance data from the same year show that those with HIV and men who have sex with men (MSM) have the highest risk for syphilis infection. The USPSTF recommends screening for syphilis in MSM and patients with HIV. When deciding whether to screen additional patients, clinicians should consider other sociodemographic factors that are associated with increased prevalence rates, including male sex combined with age younger than 29 years, race/ethnicity, geography, incarceration, and sex work, the draft recommendation said. Clinicians should also be aware of the prevalence rates of syphilis in the communities they serve.
In 2013, men accounted for 91% of all syphilis cases, and men ages 20 to 29 years had the highest prevalence rate—nearly 3 times higher than in the average U.S. male population. Prevalence rates were higher in blacks, Native Hawaiians/Pacific Islanders, and Hispanics than in other racial and ethnic groups. The southern United States comprises the largest proportion of syphilis cases, but the case rate is currently highest in the western United States, the USPSTF said. Metropolitan areas also have increased prevalence rates of syphilis.
A combination of nontreponemal and treponemal antibody tests is most commonly used to screen for syphilis, and the Task Force found evidence that available screening tests are able to accurately detect the infection. Although the optimal screening frequency for patients at increased risk for infection is not well established, initial studies suggest that detection in these patients improves when screening is performed every 3 months, compared to annual testing.
After the infection is detected, effective treatment with antibiotics can prevent progression to late-stage disease, with small associated harms. However, for nonpregnant patients who are not at increased risk for the infection, the yield of screening is likely low and will result in high false-positive rates and overtreatment, according to the Task Force.
The draft statement is open for public comment until Jan. 18, 2016.